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Increasing Registered Gross

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vmenkal(at)mac.com
Guest

Posted: Sat Aug 30, 2008 4:19 pm Post subject: Increasing Registered Gross

Thanx for the info Mark.   Gives me a better idea of what increasing  

the gross weight means in terms in real terms.     Im really treading  

softly with this until I can thoroughly understand what this change  

means in terms of satety and performance



I have a newer kit with a gross of 1100lbs and ULF of +6 and -3.   If  

I am using Chris Heinz's formula correctly, I believe that an increase  

to 1200lbs  will decrease my ULF to +5.5 and -2.75.    Based on my  

(very limited) knowledge, this still seems quite decent.



My research into this has a practical application as flying up here  

requires carrying full survival gear and folks generally dress in  

heavy clothing when outside (gets a bit chilly at times).   These  

items quickly eat into useful load.



My next research topic is to how my proposed increased gross combined  

with the extra weight of floats will impact on safety and performance.



If I may pose a question to float equipped 701 operators:    what was  

the net weight increase with floats (weight of floats less weight of  

removed landing gear) and impact on performance with your specific  

type of floats    This information will be very helpful in deciding on  

the type of floats to select for the plane, when that happy day arrives.



One last question (honest):   as useful load is important to all  

pilots, why wouldnt most builders register at the higher gross weight?



Thanx for all help folks and on an unrelated topic (apologies if this  

is not allowed) my thoughts and prayers are with anyone who may be in  

the way of Gustav.   Please stay safe and if its really nasty well be  

down with our little aid agency (aidrelief.org) to lend a hand.



Warmest Regards



Victor Menkal

Whitehorse Yukon

701 tail complete, wings being covered

Victor.



You can change the gross weight to what ever you want.  You will need to

change the load factor in your POH.  I have the old kit and have made

most of the changes to the SP, but not all.  What I have done is, using

Chris's calculations on the drawings, I will be using an 1100 lbs gross

weight with a load factor of +3.5 and -1.7.  Rather than the +4 and -2.

This will give me the same load on the aircraft.

Mark S.

701/912ULS

jetboy

Joined: 22 Jul 2006
Posts: 233

Posted: Sat Aug 30, 2008 9:31 pm Post subject: Re: Increasing Registered Gross

You also must change the POH and airspeed placard limits because vne, vfe, va are related to operations at design gross, will be lower for overgross, and what might be experienced in gust load conditions.



The fact that guidance is provided for these operations does not mean that the aircraft is legal or approved in all situations and juristictions and like practically any aircraft the 701 does not handle too well over gross and please remember the airfoil has not changed since the max gross was 880 lbs in '86 AFAIK 



I also like to carry extra clothing and gear so what I did is not fit any cockpit stuff thats not required for the mission, no extra lights, drill holes in tools and safety gear to cut weight where posible, no axe - just folding saw Silky or Gerber instead, If I were doing it again I'd consider not painting the aircraft



Also if you read carefully the latest recommendation on controls limitations for the 601XL, the same cautions would apply to a 701 over gross. Because these "advanced ultralights" by definition had to be designed light, there is practically zero margin left, over time the skins will wrinle and get weaker, its entirely up to the operator to look after his arse



Ralph

_________________
Ralph - CH701 / 2200a

kmccune

Joined: 22 Sep 2007
Posts: 577
Location: Wisconsin, USA

Posted: Sun Aug 31, 2008 5:06 am Post subject: Re: Increasing Registered Gross

That is good advise, though I doubt that the 701 is that close the the edge. The Savannah is an almost direct copy and the wing is a copy (though extended a bit) of the older 701. Yet it is rated at both a higher gross and a higher Vne. And they are not exactly falling out of the sky. Here are the  upgrade instructions from ICP to increase the gross on the older model when the 701 went to 1100lbs. They are available on the yahoo Savannah site if your wondering where I got them. When you look at them, look also at your 701 SP plans, it is interesting to say the least. 



Kevin

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_________________
“Always do what you are afraid to do.”
R.W. Emerson (1803-1882)

"Real freedom is the sustained act of being an individual." WW - 2009

"Life is a good deal...it's worth it" Feb 1969
Dorothy McCune

eightyknots

Joined: 22 Aug 2008
Posts: 5
Location: New Zealand

Posted: Mon Sep 01, 2008 10:15 pm Post subject: Re: Increasing Registered Gross

When you registered the 701 at a higher gross weight, what was the new vne, vfe and va?



The Savannah has now come up in this thread. Has anyone ever seen an honest and reliable comparison between that aircraft and the CH 701? 



Similarly, has anyone seen (or done) a comparison between the Aeroprakt A22 / Foxbat / Valor [take your pick - it has three names in different parts of the world], which is sold as a STOL kit plane?

_________________
Hank

I am looking for a STOL high-wing plane to build, starting some time during 2009. Will it be an ICP Savannah, a Zenith CH-701, an Aeroprakt Foxbat/A22/Valor, or X-Air H?

graeme(at)coletoolcentre.
Guest

Posted: Mon Sep 01, 2008 10:33 pm Post subject: Increasing Registered Gross

 	  Quote: 	
		  From a friend who flys both reguarly


	


Both good aircraft.

Savanna is faster.

Not as good in bumpy air not as good on marginal strips.

You can nail the 701 the savanna some times tends to float on.



In australia Savanna much cheaper to purchase airframe kit.

No plans Built Savanna!!



Graemecns CH701 and scratch building a second



---

vgstol(at)bigpond.net.au
Guest

Posted: Tue Sep 02, 2008 1:42 pm Post subject: Increasing Registered Gross

I have a lot of experience  with both 701 and Savannah.

 Yep, both are good  aircraft.

  

 I do lots of  x-country, and the Savannah probably is a bit bumpier than the 701 due the  larger wing, certainly not a problem.  The Savannah is more  directionally stable - I regularly cruise 3 hrs at a time without touching  the stick, just a bit of rudder pressure to hold course.  The Savannah  VG is faster than a 701 with slats, but a 701 without slats is faster than  a Savannah.

  

 On marginal strips or  off-field I'll match a Savannah with a 701 anytime - different but  equal.  Yes, the Savannah floats more, but this gives really gentle, easy  landings with good hold-off control right to touch-down at idle  speed.   With 701 pretty much need to pull it on with power all the  way - that can be good to nail a spot, but also can go wrong real quick if you  get behind the drag/power curve....  To nail the spot in the Savannah, keep  the short final speed to no more than 40kts and carry a full slip right  into round-out.  Just move the aiming point back a bit to allow for the  float and nail the spot just as well.  With such a slip approach you  can see the touchdown point right to round-out, whereas dragging on with  power can't see anything, so I much prefer it....

  

 The Foxbat has sometimes  been called, "...the rich man's Savannah..."  Much better cruise  speed, but still really good STOL for all practical purposes.  Maybe not so  suitable for really rough off-field...  Big, roomy cockpit with excellent  visibility.  A very nice aircraft, but lots more costly than 701 or  Savannah....

  

 Tailwinds  always,

 JohnG

 [quote]   ---

kmccune

Joined: 22 Sep 2007
Posts: 577
Location: Wisconsin, USA

Posted: Tue Sep 02, 2008 3:09 pm Post subject: Re: Increasing Registered Gross

OK, there you did it John  

Is the 701 in the below comparison a 701 VG? And is it a short or long wing 701?  You mentioned a slip so I am of course wondering if apples and apples or 701 slat and non-slip apples and VG Savannah slip-apples?  

Sorry for the humor, will the 701 long wing VG match the spot landings over obstacles,slip or not. of a 701 with slats and a short wing? 



PS 

Starting on my wings so I have a big decision to make in this regard, very soon.



Kevin

 

 	  apple(at)bigpond.net.au wrote: 	
		  [b]On marginal strips or  off-field I'll match a Savannah with a 701 anytime - different but  equal.  Yes, the Savannah floats more, but this gives really gentle, easy  landings with good hold-off control right to touch-down at idle  speed.   With 701 pretty much need to pull it on with power all the  way - that can be good to nail a spot, but also can go wrong real quick if you  get behind the drag/power curve....  To nail the spot in the Savannah, keep  the short final speed to no more than 40kts and carry a full slip right  into round-out.  Just move the aiming point back a bit to allow for the  float and nail the spot just as well.  With such a slip approach you  can see the touchdown point right to round-out, whereas dragging on with  power can't see anything, so I much prefer it...

vgstol(at)bigpond.net.au
Guest

Posted: Tue Sep 02, 2008 4:16 pm Post subject: Increasing Registered Gross

Gday  Kevin,

  

 In that comparison I was  imagining the 701 to be short wing with slats, and the Savannah to be  the VG model.  

  

 Yes, the 701 long wing with  VGs will get down over an obstacle just as well as a short wing with slats - at  least so close the same that we can't dependably measure any difference.   The 701 long wing VG acts more like the Savannah, so the technique is  similar, and similar benefit of a bit of float to make touchdown easier.   

  

 Slip is the key for a steep  descent in any of them, and the 701 is superior to the Savannah in that regard  due to that all-flying rudder that has heaps of power right down to nil  airspeed.  With that powerful rudder, offset by equally powerful ailrerons,  and that slab side, the 701 is the very best slipping aircraft ever.   Slipping is by far the best technique for a steeeep descent, even with slats  on.  Slipping without slats is more steady and controllable, probably due  to the slats disrupting the airflow.  Even with a 701 and slats I  prefer a steep, idle power, slipping approach for spot landings rather than  dragging on with power.  You can see the touchdown point much better, and  adjust the amount of slip to hit that point.  With the drag of  those slats this is a very steep approach and will lose speed instantly on  roundout, so better be rounding out at just the right height.....  A bit  alarming to see the ground looming up like that, but very effective to get in  really short over obstacles, and I feel more comfortable than hanging on  the prop - no chance of getting behind the power curve, or falling short due to  sink, just release the slip and extend.  The long wing VG is just a whole  lot easier to manage this maneuver.

  

 Yes Kevin, I know I've  long been promising some video to demonstrate this.  The decent  footage that I had got recorded over with junk, and need to do it  over again....  

  

 JohnG

  

 ---

vgstol(at)bigpond.net.au
Guest

Posted: Tue Sep 02, 2008 4:16 pm Post subject: Increasing Registered Gross

Will the 701 long wing VG match the spot landings over obstacles, of a 701  with slats and a short wing?

 Kevin 



  Gday  Kevin,

  

 In that comparison I was  imagining the 701 to be short wing with slats, and the Savannah to be  the VG model.  

  

 Yes, the 701 long wing with  VGs will get down over an obstacle just as well as a short wing with slats - at  least so close the same that we can't dependably measure any difference.   The 701 long wing VG acts more like the Savannah, so the technique is  similar, and similar benefit of a bit of float to make touchdown easier.   

  

 Slip is the key for a steep  descent in any of them, and the 701 is superior to the Savannah in that regard  due to that all-flying rudder that has heaps of power right down to nil  airspeed.  With that powerful rudder, offset by equally powerful ailrerons,  and that slab side, the 701 is the very best slipping aircraft ever.   Slipping is by far the best technique for a steeeep descent, even with slats  on.  Slipping without slats is more steady and controllable, probably due  to the slats disrupting the airflow.  Even with a 701 and slats I  prefer a steep, idle power, slipping approach for spot landings rather than  dragging on with power.  You can see the touchdown point much better, and  adjust the amount of slip to hit that point.  With the drag of  those slats this is a very steep approach and will lose speed instantly on  roundout, so better be rounding out at just the right height.....  A bit  alarming to see the ground looming up like that, but very effective to get in  really short over obstacles, and I feel more comfortable than hanging on  the prop - no chance of getting behind the power curve, or falling short due to  sink, just release the slip and extend.  The long wing VG is just a whole  lot easier to manage this maneuver.

  

 Yes Kevin, I know I've  long been promising some video to demonstrate this.  The decent  footage that I had got recorded over with junk, and need to do it  over again....  

  

 JohnG

  



 [quote]   ---

kmccune

Joined: 22 Sep 2007
Posts: 577
Location: Wisconsin, USA

Posted: Tue Sep 02, 2008 5:22 pm Post subject: Re: Increasing Registered Gross

That should be Good Day Eh! (well at least here)  



Thanks John and no worries about the videos here mate!  

PS Welcome home...long trip !



Kevin

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